A milky, gray pall entirely blocks the ground from view in the top image, taken in the early afternoon by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. Patches of white fog or low cloud hang below the gray haze. Winds had already begun to push the haze out of Beijing in the north, but the rest of the North China Plain still suffered from poor air quality.

As the images show, by the next day most of the smog had gone, but it really shows just how dramatic the smog has been for those living in China: